Diabetes is a common life-long health condition. There are 3.5 million people diagnosed with diabetes in the UK and an estimated 500,000 who are living undiagnosed with the condition.

People should be aware signs and symptoms of diabetes are not always obvious and the condition is often diagnosed during GP check ups.

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Diabetes diagnosis: Having particular genes can stop the test from working

The G6PD genetic variant is almost unique to people with African ancestry.

The researchers have suggested that particular groups with such ancestry are screened for the genetic variant alongside the blood test to improve diagnosis of type 2.

In the study, researchers looked at the genetic variants of around 160,000 people from European, African, East Asian and South Asian ancestries who were not known to have the condition.

“The issue with the G6PD genetic variant is it artificially lowers the value of blood sugar in the HbA1c test, and can lead to under-diagnosis of people with type 2 diabetes,” said Dr Inês Barroso, a study author.

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Diabetes diagnosis: There are an estimated four million sufferers in the UK

“However, the HbA1c test remains a suitable test for diagnosing and monitoring diabetes for the majority of people.”

The HbA1c test works by measuring the amount of glucose, or sugar that is carried by the red blood cells in the body, for the previous two to three months.

There are an estimated 4 million people living in the UK, which includes thought to be undiagnosed.